“Landline” explores the upper-middle-class family dynamics of disconnection, lies and secrets. After a well-received premiere at the Sundance Film Festival last January, Amazon Studios picked up the film. It opens in Boston theaters July 28.

By Jody Feinberg/The Patriot Ledger

Riding in a car with her family, Dana – played by Milton actress Jenny Slate in the new film “Landline” – mishears the lyrics to the 1990s radio hit “Bring Me a Higher Love.” She’s just had mosquito-interrupted sex in the woods with her unromantic fiance and thinks the words are “break me a higher love.” She and her teenage sister, Ali, spar, and in the front seat, their parents seem so separate they could be in another vehicle.

In this comic snapshot, “Landline” director Gillian Robespierre sets up the upper-middle-class family dynamics of disconnection, lies and secrets.

“It’s the ’90s, so no one is buried in their individual cellphones,” said Robespierre, who wrote the script with producer Elisabeth Holm. “We thought, ‘Let’s take this family, roll up the windows, blast the song and expose them.’”

After a well-received premiere at the Sundance Film Festival last January, Amazon Studios picked up the film for a reported $3 million. It opens in Boston theaters July 28.

Three years after Robespierre and Slate won critics’ awards for the film “Obvious Child,” the two return with a more ambitious movie with an ensemble of characters and multiple story lines. These are people who keep truths from each other and disregard those closest to them, until they realize the damage they’ve caused.

“We called it ‘Landline’ because the movie is about people connecting, and in the ’90s, a land line was the way people connected,” said Holm, 30, who met Robespierre at a film mixer in New York city.

Robespierre and Holm wrote the part of Dana specifically for Slate, who grew up in Milton and was valedictorian of her Milton Academy class in 2000. She has starred and had voice roles in many films, including the Oscar-winning animated movie “Zootopia,” “The Lego Batman Movie” and this summer’s “Despicable Me 3.” Other film credits are “Gifted,” starring opposite Sudbury’s Chris Evans, and the indie “My Blind Brother.” Slate is also ubiquitous in supporting and guest roles on TV comedies such as “Brooklyn Nine Nine” “Parks and Recreation,” “House of Lies” and “Girls.”

“We were excited to team up again and we wanted to challenge ourselves,” said Robespierre, who met Slate when she saw her do stand-up comedy. “We wrote for her tone and her abilities, but we also wanted to weave together different stories.”

“Landline” is the story of sisters Dana (Slate) and Ali (Abby Quinn) who have little use for each other, until Ali discovers on a floppy-disc computer the romantic poems written by their father (John Turturro), a frustrated playwright who works in advertising. They bond over their efforts to discover his lover and shield their mother (Edie Falco), a businesswoman struggling with little help from her husband to control rebellious, disdainful Ali.

Once strangers to each other, the sisters grow closer as they discover their parallel stories of deception: Dana cheats on her sweet, but unexciting, fiance (Jay Duplass), and Ali lies repeatedly, skipping school, snorting heroin and having sex.

“We tried to make every character human and realistic,” Robespierre said. “They’re flawed and make big mistakes, but through honesty (and concern for their mother), they start to feel connected.”

The idea for the film came from the writers’ experiences as New York City teenagers whose parents divorced.

“We wanted to flip the divorce narrative of everything breaking down,” said Robespierre, 39, married and the mother of a 2-year-old. “Instead of our families falling apart, we came together in a new way. Our siblings became our pals, and our moms became women who had diverse sides. It changed the shape of our family dynamics and communication for the better.”

Over the course of the film (whose lighter moments include a water fight, a Halloween parade, uninhibited dancing, and a payphone conversation), there are confessions and questions about commitment, choice and loyalty.

While Dana comically melts down when she flees home to take a break from her fiance and later begs him to let her return, Ali hangs tough. When she starts to feel a little empathy and appreciation, she is particularly compelling.

“It felt cathartic to play Ali, because she would say whatever she was feeling and make direct eye contact,” said Quinn, 21, who had her first film role in 2014 (“The Sisterhood of Night”) and lives in Los Angeles. “She isn’t really malicious, though she may seem to be. When she realizes her parents aren’t doing OK, she starts to see her vulnerability and to want to connect with her family.”

In the final scene where they celebrate Ali’s birthday, each family member knows the messy truth.

“We want to leave the audience with the sense that this family has a tough road ahead, but they are going to be there for each other, even if it’s not under the same roof,” Robespierre said.

Jody Feinberg may be reached at jfeinberg@ledger.com or follow her on Twitter @JodyF_Ledger.